Peripheral Blood Monocyte Subpopulations Research Articles

The peripheral blood monocyte subpopulations in normal subjects and and patients with angina pectoris: I.Kondakov, N.Menzianova, A.Kubatiev. Central Institute of Postgraduate Medical Training, Moscow, USSR

The peripheral blood monocyte subpopulations in normal subjects and and patients with angina pectoris: I.Kondakov, N.Menzianova, A.Kubatiev. Central Institute of Postgraduate Medical Training, Moscow, USSR

Immunoregulation of lymphoproliferation in vitro by monocytes and their subpopulations. I. The induction of suppressor T cells in long term cultures and the role of MHC class II determinants and preliminary characteristics.

Peripheral blood monocyte (MO) subpopulations isolated on a basis of functional expression or a lack of Fc receptor (FcR+ and FcR- MO) were used to study the regulation of the antigen (PPD)-driven lymphoproliferation. Long-term cultures of T lymphocytes with FcR+ MO, but not FcR- MO, led to the induction of T suppressor (Ts) cells that inhibited antigen-driven lymphoproliferation in the test cultures. These Ts cells were resistant to mitomycin C, belonged to afferent-acting category of Ts cells, expressed CD8 and HLA-DR determinants, and showed no antigenic specificity nor genetic restriction in action. The expression of MHC class II molecules (HLA-DR and HLA-DP but not HLA-DQ determinants) on MO which were used for antigen presentation was critical for Ts cell induction. It was concluded that specialized MO subpopulations may regulate the lymphoproliferation by inducing Ts cells (or Ts cell circuit) that in turn inhibit antigen-driven immune response.

Expression of the VEP13 Antigen (CD16) on Native Human Alveolar Macrophages and Cultured Blood Monocytes

Human alveolar macrophages (AM) from thirteen patients, who were suffering from various lung diseases were harvested by bronchoalveolar lavage. Peripheral blood monocytes from eight healthy donors were isolated by Ficoll-Hypaque gradient centrifugation and adherence to plastic surface. To detect the VEP13 antigen (CD16) on these cells, a rosette assay employing ox erythrocytes coated by the CrCl 3 method with purified VEP13 monoclonal antibody (E o-VEP13) was used. A mean of 31.3 % of freshly isolated AM and 3.9 % of blood monocytes formed E o-VEP13 rosettes. Monocytes cultured for 3 or 6 days in the presence of a supernatant from mouse L929 cells, which had been shown previously to improve long-term viability of human monocytes in culture, showed 12.5 % and 25.3 % E o-VEP13 rosettes, respectively. No significant increase in VEP13 antigen expression was noted by culturing monocytes without L929 cell supernatant. The factor in L929 supernatant that induces VEP13 antigen expression has not been identified. Tunicamycin at 10 υg/ml inhibited significantly VEP13 antigen expression on monocytes. In contrast, IgG rosette formation was not reduced by tunicamycin. Our data show that subpopulations of native human AM and peripheral blood monocytes cultured in presence of a supernatant of L929 fibroblasts containing mainly murine CSF may express the CD16 antigen, which is normally found on large granular lymphocytes (LGL). Suppression by tunicamycin indicates that Fc receptor glycosylation takes place during a later differentiation step of mononuclear phagocytes.

Differences in Fc receptor expression between small and large guinea pig monocytes.

Guinea pig monocytes have been separated into subpopulations differing in size, morphology, and cytochemistry. We report now that these peripheral blood monocyte subpopulations differ also in native Fc receptor expression. All freshly isolated small monocytes formed Fc rosettes with sensitized sheep erythrocytes, whereas Fc receptor expression was not detectable on large monocytes. However, Fc receptor expression developed rapidly in culture such that by 48 hours all monocytes were positive. This phenomenon was inhibited by 2-deoxy-D-glucose and cycloheximide, suggesting that Fc receptor expression depended upon glycolysis and protein synthesis. Large monocytes participated in antibody-dependent lysis of sheep erythrocyte targets. That large monocytes lacking Fc receptors were cytolytic in this assay was concordant with expression of Fc receptors during the 16-hour test period. We believe that the large number of lymphocytes present in the Fc receptor-positive small monocyte fraction interfered with their measurement of antibody-dependent cytotoxicity. We conclude that Fc receptor expression on guinea pig monocytes is heterogeneous within the peripheral circulation. These differences quickly diminish in vitro with the expression of Fc receptors by all monocytes. Additionally, antibody-dependent lysis of sensitized erythrocytes by guinea pig mononuclear cells is due to monocytes and not lymphocytes or Kurloff cells.

Immuno-electron microscopic tracing of lactoferrin, a regulator of myelopoiesis, into a subpopulation of human peripheral blood monocytes.

Lactoferrin (LF), an iron binding glycoprotein present in the specific granules of mature granulocytes, is capable of suppressing the production of granulocyte-macrophage colony stimulatory factors (GM-CSF) by monocytes and macrophages in vitro and rebound myelopoiesis in vivo. By an immuno-electron microscopic technique (peroxidase-antiperoxidase procedure) in combination with a three-step fixation and detergent treatment of mononuclear blood cells pulsed with LF, intracellular localization of LF in a sub-population of human monocytes with a well-preserved subcellular morphology was demonstrated. LF was found in the monocytes after a 30 min pulse with concentrations of LF as low as 10(-14) M. Under the electron microscope, deposits of approximately 110 nm diameter appeared scattered in the area of the endoplasmic reticulum. Large numbers of smaller deposits (20-70 nm) were found in the euchromatin. The heterochromatin and other cytoplasmic organelles were free of LF. These results suggest that the euchromatin might be the functional site for LF inhibition of the production of GM-CSF by a subpopulation of human monocytes.

Fc receptors for IgE on a subpopulation of human peripheral blood monocytes.

Fc receptors for IgE on a subpopulation of human peripheral blood monocytes.

Monocyte Subsets in Neonates and Children

Volumetrically distinct subpopulations of peripheral blood monocytes, termed M1, M2, and M3, were identified in healthy normal adults and children. Because normal neonates have abnormal monocyte chemotaxis, it was determined whether monocyte subpopulations have different chemotactic capabilities and, if so, whether chemotactically active subpopulations were quantitatively deficient in neonates. Chemotaxis tests with zymosan-activated normal human serum as the chemoattractant and purified monocyte subpopulations revealed that large M3 monocytes were capable of significantly more directed migration than were small M1 and M2 monocytes. Volumetric analysis of monocytes from normal newborns rather than demonstrating an absence of M3 cells revealed that these cells were the predominant monocyte subpopulation. Therefore, we conclude that the impaired chemotactic ability of newborn monocytes is due to a functional rather than quantitative deficiency of M3 cells.

Synthesis of prostaglandins by subpopulations of human peripheral blood monocytes

The ability of monocytes/macrophages to regulate various aspects of immunologic responses may in part depend on their release of soluble substances such as prostaglandins. Using quantitative gas-liquid chromatography/mass spectrometry, prostaglandin E 2 was found to be the major prostaglandin synthesized in culture by human peripheral blood monocytes. Subjecting these cells to discontinuous density gradient fractionation demonstrated significant differences in the synthesis of prostaglandins E 2 and E 1 among the resulting monocyte subpopulations.